1 // Boost.Geometry (aka GGL, Generic Geometry Library)
2
3 // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
4 // Copyright (c) 2008-2012 Barend Gehrels, Amsterdam, the Netherlands.
5 // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
6
7 // Use, modification and distribution is subject to the Boost Software License,
8 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
9 // http://www.boost.org/LICENSE_1_0.txt)
10
11 #ifndef BOOST_GEOMETRY_ARITHMETIC_DETERMINANT_HPP
12 #define BOOST_GEOMETRY_ARITHMETIC_DETERMINANT_HPP
13
14
15 #include <cstddef>
16
17 #include <boost/geometry/core/access.hpp>
18 #include <boost/geometry/geometries/concepts/point_concept.hpp>
19 #include <boost/geometry/util/select_coordinate_type.hpp>
20
21 #include <boost/numeric/conversion/cast.hpp>
22
23 namespace boost { namespace geometry
24 {
25
26 #ifndef DOXYGEN_NO_DETAIL
27 namespace detail
28 {
29
30 template <typename ReturnType, typename U, typename V>
31 class calculate_determinant
32 {
33 template <typename T>
rt(T const & v)34 static inline ReturnType rt(T const& v)
35 {
36 return boost::numeric_cast<ReturnType>(v);
37 }
38
39 public :
40
apply(U const & ux,U const & uy,V const & vx,V const & vy)41 static inline ReturnType apply(U const& ux, U const& uy
42 , V const& vx, V const& vy)
43 {
44 return rt(ux) * rt(vy) - rt(uy) * rt(vx);
45 }
46 };
47
48 template <typename ReturnType, typename U, typename V>
determinant(U const & ux,U const & uy,V const & vx,V const & vy)49 inline ReturnType determinant(U const& ux, U const& uy
50 , V const& vx, V const& vy)
51 {
52 return calculate_determinant
53 <
54 ReturnType, U, V
55 >::apply(ux, uy, vx, vy);
56 }
57
58
59 template <typename ReturnType, typename U, typename V>
determinant(U const & u,V const & v)60 inline ReturnType determinant(U const& u, V const& v)
61 {
62 BOOST_CONCEPT_ASSERT( (concepts::ConstPoint<U>) );
63 BOOST_CONCEPT_ASSERT( (concepts::ConstPoint<V>) );
64
65 return calculate_determinant
66 <
67 ReturnType,
68 typename geometry::coordinate_type<U>::type,
69 typename geometry::coordinate_type<V>::type
70 >::apply(get<0>(u), get<1>(u), get<0>(v), get<1>(v));
71 }
72
73 } // namespace detail
74 #endif // DOXYGEN_NO_DETAIL
75
76 }} // namespace boost::geometry
77
78 #endif // BOOST_GEOMETRY_ARITHMETIC_DETERMINANT_HPP
79